1. Technical Field
The present disclosure relates to a nonaqueous electrolyte secondary battery and a method of manufacturing a nonaqueous electrolyte secondary battery.
2. Description of Related Art
When a lithium ion secondary battery is charged and discharged, oxidative decomposition of a nonaqueous electrolytic solution may occur. In a lithium ion secondary battery in which an acid is produced by the oxidative decomposition of a nonaqueous electrolytic solution, a transition metal may be eluted from a positive electrode active material due to the acid. In a case where a transition metal is eluted from a positive electrode active material, the capacity retention of a lithium ion secondary battery may decrease.
For example, Japanese Patent Application Publication No. 2014-103098 (JP 2014-103098 A) discloses a nonaqueous electrolyte secondary battery including a positive electrode active material layer that includes a positive electrode active material and trilithium phosphate as an additive. According to JP 2014-103098 A, by the positive electrode active material layer including trilithium phosphate, the elution of a transition metal from the positive electrode active material during the charging and discharging of the nonaqueous electrolyte secondary battery can be prevented. Specifically, trilithium phosphate can function as an acid consuming material by reacting with hydrofluoric acid (HF) produced in the nonaqueous electrolytic solution. As a result, the elution of a transition metal from the positive electrode active material can be prevented, and the durability of the nonaqueous electrolyte secondary battery can be improved.